Delegates to an international conference on the Convention on Cluster Munitions have unanimously adopted a document expressing strong concerns over the use of the highly lethal weapon in Ukraine.

The convention bans the production, stockpiling, use and transfer of the weapons. More than 110 countries, including Japan, have ratified or acceded to the pact.

Cluster munitions are being used in Ukraine by Russia, which has not signed on to the convention. Ukraine is also using such weapons supplied by the United States.

The delegates wrapped up the meeting of state parties to the convention on Thursday. The meeting began on Monday in the UN office in Geneva, Switzerland.

On Thursday, state members confirmed and welcomed the progress they have made in the abolition of cluster munitions and the disposal of their remnants.

During the meeting, the members criticized Russia for its use of cluster munitions in Ukraine. But they were divided over the use of cluster munitions by Ukraine and the US supplying the munitions to the country.

The members avoided directly referring to specific countries in the document to send a unified message as cluster munition casualties are increasing in the war in Ukraine.

Cluster munitions are highly lethal as they open in the air to disperse multiple bomblets over a wide area. Many bomblets fail to explode on initial impact, leaving remnants that can indiscriminately kill or injure civilians for years until they are cleared.